How to use the bs-platform/lib/js/js_json.js.decodeNull function in bs-platform

tmp = match$1[0].map((function (value) {
              var match = Js_json.decodeObject(value);
              if (match) {
                var value$1 = match[0];
                var value$2 = value$1["uid"];
                var match$1 = Js_json.decodeString(value$2);
                var tmp;
                if (match$1) {
                  tmp = match$1[0];
                } else {
                  throw Graphql_error;
                }
                var value$3 = value$1["image"];
                var match$2 = Js_json.decodeNull(value$3);
                var tmp$1;
                if (match$2) {
                  tmp$1 = /* None */0;
                } else {
                  var match$3 = Js_json.decodeObject(value$3);
                  var tmp$2;
                  if (match$3) {
                    var value$4 = match$3[0]["small"];
                    var match$4 = Js_json.decodeString(value$4);
                    var tmp$3;
                    if (match$4) {
                      tmp$3 = match$4[0];
                    } else {
                      throw Graphql_error;
                    }
                    tmp$2 = {

href: tmp$14,
                            album: tmp$15
                          };
                        } else {
                          tmp$9 = Js_exn.raiseError("graphql_ppx: Object is not a value");
                        }
                        tmp$8 = Caml_option.some(tmp$9);
                      }
                    } else {
                      tmp$8 = undefined;
                    }
                    var match$42 = Js_dict.get(value$5, "progressMs");
                    var tmp$18;
                    if (match$42 !== undefined) {
                      var value$17 = Caml_option.valFromOption(match$42);
                      var match$43 = Js_json.decodeNull(value$17);
                      if (match$43 !== undefined) {
                        tmp$18 = undefined;
                      } else {
                        var match$44 = Js_json.decodeNumber(value$17);
                        tmp$18 = match$44 !== undefined ? match$44 | 0 : Js_exn.raiseError("graphql_ppx: Expected int, got " + JSON.stringify(value$17));
                      }
                    } else {
                      tmp$18 = undefined;
                    }
                    tmp$5 = {
                      isPlaying: tmp$6,
                      currentlyPlayingType: tmp$7,
                      item: tmp$8,
                      progressMs: tmp$18
                    };
                  } else {

var match$36 = Js_dict.get(value$9, "album");
                          var tmp$15;
                          if (match$36 !== undefined) {
                            var value$15 = Caml_option.valFromOption(match$36);
                            var match$37 = Js_json.decodeNull(value$15);
                            if (match$37 !== undefined) {
                              tmp$15 = undefined;
                            } else {
                              var match$38 = Js_json.decodeObject(value$15);
                              var tmp$16;
                              if (match$38 !== undefined) {
                                var match$39 = Js_dict.get(Caml_option.valFromOption(match$38), "images");
                                var tmp$17;
                                if (match$39 !== undefined) {
                                  var value$16 = Caml_option.valFromOption(match$39);
                                  var match$40 = Js_json.decodeNull(value$16);
                                  if (match$40 !== undefined) {
                                    tmp$17 = undefined;
                                  } else {
                                    var match$41 = Js_json.decodeArray(value$16);
                                    tmp$17 = match$41 !== undefined ? match$41.map((function (value) {
                                              var match = Js_json.decodeObject(value);
                                              if (match !== undefined) {
                                                var match$1 = Js_dict.get(Caml_option.valFromOption(match), "url");
                                                var tmp;
                                                if (match$1 !== undefined) {
                                                  var value$1 = Caml_option.valFromOption(match$1);
                                                  var match$2 = Js_json.decodeNull(value$1);
                                                  if (match$2 !== undefined) {
                                                    tmp = undefined;
                                                  } else {
                                                    var match$3 = Js_json.decodeString(value$1);

var value$14 = Caml_option.valFromOption(match$33);
                            var match$34 = Js_json.decodeNull(value$14);
                            if (match$34 !== undefined) {
                              tmp$14 = undefined;
                            } else {
                              var match$35 = Js_json.decodeString(value$14);
                              tmp$14 = match$35 !== undefined ? match$35 : Js_exn.raiseError("graphql_ppx: Expected string, got " + JSON.stringify(value$14));
                            }
                          } else {
                            tmp$14 = undefined;
                          }
                          var match$36 = Js_dict.get(value$9, "album");
                          var tmp$15;
                          if (match$36 !== undefined) {
                            var value$15 = Caml_option.valFromOption(match$36);
                            var match$37 = Js_json.decodeNull(value$15);
                            if (match$37 !== undefined) {
                              tmp$15 = undefined;
                            } else {
                              var match$38 = Js_json.decodeObject(value$15);
                              var tmp$16;
                              if (match$38 !== undefined) {
                                var match$39 = Js_dict.get(Caml_option.valFromOption(match$38), "images");
                                var tmp$17;
                                if (match$39 !== undefined) {
                                  var value$16 = Caml_option.valFromOption(match$39);
                                  var match$40 = Js_json.decodeNull(value$16);
                                  if (match$40 !== undefined) {
                                    tmp$17 = undefined;
                                  } else {
                                    var match$41 = Js_json.decodeArray(value$16);
                                    tmp$17 = match$41 !== undefined ? match$41.map((function (value) {

var tmp$4;
              if (match$9 !== undefined) {
                var value$4 = Caml_option.valFromOption(match$9);
                var match$10 = Js_json.decodeNull(value$4);
                if (match$10 !== undefined) {
                  tmp$4 = undefined;
                } else {
                  var match$11 = Js_json.decodeObject(value$4);
                  var tmp$5;
                  if (match$11 !== undefined) {
                    var value$5 = Caml_option.valFromOption(match$11);
                    var match$12 = Js_dict.get(value$5, "isPlaying");
                    var tmp$6;
                    if (match$12 !== undefined) {
                      var value$6 = Caml_option.valFromOption(match$12);
                      var match$13 = Js_json.decodeNull(value$6);
                      if (match$13 !== undefined) {
                        tmp$6 = undefined;
                      } else {
                        var match$14 = Js_json.decodeBoolean(value$6);
                        tmp$6 = match$14 !== undefined ? match$14 : Js_exn.raiseError("graphql_ppx: Expected boolean, got " + JSON.stringify(value$6));
                      }
                    } else {
                      tmp$6 = undefined;
                    }
                    var match$15 = Js_dict.get(value$5, "currentlyPlayingType");
                    var tmp$7;
                    if (match$15 !== undefined) {
                      var value$7 = Caml_option.valFromOption(match$15);
                      var match$16 = Js_json.decodeNull(value$7);
                      if (match$16 !== undefined) {
                        tmp$7 = undefined;

var value$6 = Caml_option.valFromOption(match$12);
                      var match$13 = Js_json.decodeNull(value$6);
                      if (match$13 !== undefined) {
                        tmp$6 = undefined;
                      } else {
                        var match$14 = Js_json.decodeBoolean(value$6);
                        tmp$6 = match$14 !== undefined ? match$14 : Js_exn.raiseError("graphql_ppx: Expected boolean, got " + JSON.stringify(value$6));
                      }
                    } else {
                      tmp$6 = undefined;
                    }
                    var match$15 = Js_dict.get(value$5, "currentlyPlayingType");
                    var tmp$7;
                    if (match$15 !== undefined) {
                      var value$7 = Caml_option.valFromOption(match$15);
                      var match$16 = Js_json.decodeNull(value$7);
                      if (match$16 !== undefined) {
                        tmp$7 = undefined;
                      } else {
                        var match$17 = Js_json.decodeString(value$7);
                        tmp$7 = match$17 !== undefined ? match$17 : Js_exn.raiseError("graphql_ppx: Expected string, got " + JSON.stringify(value$7));
                      }
                    } else {
                      tmp$7 = undefined;
                    }
                    var match$18 = Js_dict.get(value$5, "item");
                    var tmp$8;
                    if (match$18 !== undefined) {
                      var value$8 = Caml_option.valFromOption(match$18);
                      var match$19 = Js_json.decodeNull(value$8);
                      if (match$19 !== undefined) {
                        tmp$8 = undefined;

var value$13 = Caml_option.valFromOption(match$30);
                            var match$31 = Js_json.decodeNull(value$13);
                            if (match$31 !== undefined) {
                              tmp$13 = undefined;
                            } else {
                              var match$32 = Js_json.decodeNumber(value$13);
                              tmp$13 = match$32 !== undefined ? match$32 | 0 : Js_exn.raiseError("graphql_ppx: Expected int, got " + JSON.stringify(value$13));
                            }
                          } else {
                            tmp$13 = undefined;
                          }
                          var match$33 = Js_dict.get(value$9, "href");
                          var tmp$14;
                          if (match$33 !== undefined) {
                            var value$14 = Caml_option.valFromOption(match$33);
                            var match$34 = Js_json.decodeNull(value$14);
                            if (match$34 !== undefined) {
                              tmp$14 = undefined;
                            } else {
                              var match$35 = Js_json.decodeString(value$14);
                              tmp$14 = match$35 !== undefined ? match$35 : Js_exn.raiseError("graphql_ppx: Expected string, got " + JSON.stringify(value$14));
                            }
                          } else {
                            tmp$14 = undefined;
                          }
                          var match$36 = Js_dict.get(value$9, "album");
                          var tmp$15;
                          if (match$36 !== undefined) {
                            var value$15 = Caml_option.valFromOption(match$36);
                            var match$37 = Js_json.decodeNull(value$15);
                            if (match$37 !== undefined) {
                              tmp$15 = undefined;

var tmp$1;
        if (match$3 !== undefined) {
          var value$1 = Caml_option.valFromOption(match$3);
          var match$4 = Js_json.decodeNull(value$1);
          if (match$4 !== undefined) {
            tmp$1 = undefined;
          } else {
            var match$5 = Js_json.decodeObject(value$1);
            var tmp$2;
            if (match$5 !== undefined) {
              var value$2 = Caml_option.valFromOption(match$5);
              var match$6 = Js_dict.get(value$2, "id");
              var tmp$3;
              if (match$6 !== undefined) {
                var value$3 = Caml_option.valFromOption(match$6);
                var match$7 = Js_json.decodeNull(value$3);
                if (match$7 !== undefined) {
                  tmp$3 = undefined;
                } else {
                  var match$8 = Js_json.decodeString(value$3);
                  tmp$3 = match$8 !== undefined ? match$8 : Js_exn.raiseError("graphql_ppx: Expected string, got " + JSON.stringify(value$3));
                }
              } else {
                tmp$3 = undefined;
              }
              var match$9 = Js_dict.get(value$2, "displayName");
              var tmp$4;
              if (match$9 !== undefined) {
                var value$4 = Caml_option.valFromOption(match$9);
                var match$10 = Js_json.decodeNull(value$4);
                if (match$10 !== undefined) {
                  tmp$4 = undefined;

var value$7 = Caml_option.valFromOption(match$15);
                      var match$16 = Js_json.decodeNull(value$7);
                      if (match$16 !== undefined) {
                        tmp$7 = undefined;
                      } else {
                        var match$17 = Js_json.decodeString(value$7);
                        tmp$7 = match$17 !== undefined ? match$17 : Js_exn.raiseError("graphql_ppx: Expected string, got " + JSON.stringify(value$7));
                      }
                    } else {
                      tmp$7 = undefined;
                    }
                    var match$18 = Js_dict.get(value$5, "item");
                    var tmp$8;
                    if (match$18 !== undefined) {
                      var value$8 = Caml_option.valFromOption(match$18);
                      var match$19 = Js_json.decodeNull(value$8);
                      if (match$19 !== undefined) {
                        tmp$8 = undefined;
                      } else {
                        var match$20 = Js_json.decodeObject(value$8);
                        var tmp$9;
                        if (match$20 !== undefined) {
                          var value$9 = Caml_option.valFromOption(match$20);
                          var match$21 = Js_dict.get(value$9, "id");
                          var tmp$10;
                          if (match$21 !== undefined) {
                            var value$10 = Caml_option.valFromOption(match$21);
                            var match$22 = Js_json.decodeNull(value$10);
                            if (match$22 !== undefined) {
                              tmp$10 = undefined;
                            } else {
                              var match$23 = Js_json.decodeString(value$10);

var value$11 = Caml_option.valFromOption(match$24);
                            var match$25 = Js_json.decodeNull(value$11);
                            if (match$25 !== undefined) {
                              tmp$11 = undefined;
                            } else {
                              var match$26 = Js_json.decodeString(value$11);
                              tmp$11 = match$26 !== undefined ? match$26 : Js_exn.raiseError("graphql_ppx: Expected string, got " + JSON.stringify(value$11));
                            }
                          } else {
                            tmp$11 = undefined;
                          }
                          var match$27 = Js_dict.get(value$9, "artists");
                          var tmp$12;
                          if (match$27 !== undefined) {
                            var value$12 = Caml_option.valFromOption(match$27);
                            var match$28 = Js_json.decodeNull(value$12);
                            if (match$28 !== undefined) {
                              tmp$12 = undefined;
                            } else {
                              var match$29 = Js_json.decodeArray(value$12);
                              tmp$12 = match$29 !== undefined ? match$29.map((function (value) {
                                        var match = Js_json.decodeObject(value);
                                        if (match !== undefined) {
                                          var match$1 = Js_dict.get(Caml_option.valFromOption(match), "name");
                                          var tmp;
                                          if (match$1 !== undefined) {
                                            var value$1 = Caml_option.valFromOption(match$1);
                                            var match$2 = Js_json.decodeNull(value$1);
                                            if (match$2 !== undefined) {
                                              tmp = undefined;
                                            } else {
                                              var match$3 = Js_json.decodeString(value$1);